Viscosifier and fluid loss control system
AssigneeW. R. Grace & Co.
InventorJacob Block
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Abstract
A composition capable of imparting pseudoplasticity and fluid loss control properties to aqueous systems. The composition is formed from a combination of: (a) a hydroxy containing aluminum component and (b) a reaction product of a polyvinyl alcohol and at least 1 percent of stoichiometry of an aldehyde containing or generating agent; wherein the amount of component (a) to component (b) is in the ratio of at least about 0.75:1. The invention is further directed to improved drilling fluids containing said composition and to the process of drilling bore holes using said improved fluid.
Claims11
A composition capable of imparting to clay-free aqueous systems a combination of pseudoplasticity and fluid loss control comprising a mixture of:
- (a) a hydroxy containing aluminum component formed by mixing in an aqueous medium and under a high degree of agitation of water-soluble basic agent selected from the group consisting of an alkali metal aluminate, alkali metal hydroxide, ammonium hydroxide and mixtures thereof with a water-soluble acidic agent selected from an inorganic acid, aluminum chloride, aluminum sulfate, aluminum nitrate, their hydrates and mixtures thereof;
- at least one of said basic and acidic agents being an aluminum containing compound:
- said acidic and basic agents being reacted in a ratio such that the resultant product imparts to said aqueous medium pH of from at least about 8 to about 10.3;
- in combination with
- (b) a reaction product formed in an aqueous acidic medium having a pH of less than about 5.5 between polyvinyl alcohol having a weight average molecular weight of at least 20,000 with at least 1 percent of stoichiometry of a compound containing at least one aldehyde group therein or capable of generating in situ at least one aldehyde group;
- wherein the amount of component (a) to component (b) is in the weight ratio of at least about 0.75:1.
A composition capable of imparting to clay-free aqueous systems a combination of pseudoplasticity and fluid loss control comprising a mixture of:
- (a) a hydroxy containing aluminum component formed by mixing in an aqueous medium and under a high degree of agitation a water-soluble basic agent selected from the group consisting of an alkali metal aluminate, alkali metal hydroxide, ammonium hydroxide and mixtures thereof with a water-soluble acidic agent selected from an inorganic acid, aluminum chloride, aluminum sulfate, aluminum nitrate, their hydrates and mixtures thereof;
- at least one of said basic and acidic agents being an aluminum containing compound:
- said acidic and basic agents being reacted in a ratio such that the resultant product imparts to said aqueous medium a pH of from at least about 8 to about 10.3;
- in combination with
- (b) a reaction product formed in an aqueous acidic medium having a pH of less than about 5.5 between polyvinyl alcohol having a weight average molecular weight of at least 20,000 and is at least about 75 percent hydrolyzed with from about 1 to 200 percent of stoichiometry of a compound containing at least one aldehyde group therein or capable of generating in situ at least one aldehyde group, said compound selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, glycolaldehyde, glyoxalic acid, glyoxal, paraformaldehyde, tri(methylol) melamine, hexa(methylol) melamine, tri(C.sub.1 -C.sub.3 alkoxymethyl) melamine and hexa(C.sub.1 -C.sub.3 alkoxymethyl) melamine;
- wherein the amount of component (a) to component (b) is in the weight ratio of from about 0.75:1 to about 3:1.
Dependencies are inferred from the claim text.